Given n cubes 1*1*1 (x, y, z) and n types of pigments . You can choose any one of the n pigments to paint every face of these cubes as you want. To save space, we’d like you to stack these n cubes vertically into a 1*1*n cube. What’s more, to make it as much beautiful as possible, we demand you to find a painting way to make sure that all the vertical faces of the resulting cube are covered by n colors.
For example, such as n = 4, a cube's expand map just as sample 1-1 ;and the stacked cube's expand map just as sample 1-2;